Earnings Per Share - Reconciliation of Diluted Shares Outstanding (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Earnings Per Share [Abstract]
Number of options to purchase Class A shares excluded	2,523,500	1,199,000	2,548,500	1,199,000